The Liquid Crystal Display (LCD) possesses advantages of thin body, power saving and no radiation to be widely used in many application scope. Such as LCD TV, mobile phone, personal digital assistant (PDA), digital camera, notebook, laptop, and dominates the flat panel display field.
Most of the liquid crystal displays on the present market are back light type liquid crystal displays, which comprise a shell, a liquid crystal display panel located in the shell and a backlight module located in the shell. The liquid crystal display panel is a major component of the liquid crystal display. However, the liquid crystal display panel itself does not emit light and needs the back light module to provide light source for normally showing images.
Generally, the liquid crystal display panel comprises a Color Filter (CF), a Thin Film Transistor Array Substrate (TFT Array Substrate) and a Liquid Crystal Layer positioned between the two substrates. Meanwhile, pixel electrodes, common electrodes are provided respectively at relative inner sides of the two substrates. The light of back light module is reflected to generate images by applying voltages to control the liquid crystal molecules to be changed directions.
The liquid crystal displays have kinds of display types, including Twisted Nematic (TN) type, Electrically Controlled Birefringence (ECB) type, Vertical Alignment (VA) type and et cetera. The VA type is a common display type with benefits of high contrast, wide view angle and rubbing alignment free. However, because the VA type utilizes vertical twist liquid crystals and the birefraction difference of the liquid crystal molecules is larger, the issue of the color shift under large view angle is more serious.
Reducing the color shift is the requirement for the development of the VA type liquid crystal displays. At present, the mainstream method of solving the color shift of the VA type liquid crystal displays is multi domain, such as a pixel design of 8 domain display. The twisted angles of the liquid crystal molecules of the 4 domains in the main area (main) and the 4 domains in the sub area (sub) in the same sub pixel are different to improve the color shift. The color shift improvement skill mainly comprises capacitor coupling (CC) technology, charge sharing (CS) technology, common electrode voltage (Vcom) modulation technology, 2D1G/2G1D technology.
Please refer to FIG. 1. FIG. 1 is a diagram of a pixel structure utilizing 2D1G technology according to prior art. As shown in FIG. 1, a plurality of sub pixels arranged in array in a liquid crystal panel, and each sub pixel is divided into a main area Main and a sub area Sub of which the areas are unequal. The main area Main and the sub area Sub in the same row shares the same scan line Gn. The sub pixels in the same column employ two data signal lines Data1, Data2 with different voltages to respectively input data signals to the main area Main and the sub area Sub. Please refer to FIG. 2. FIG. 2 is a diagram of a sub pixel circuit shown in FIG. 1. As shown in FIG. 2, the main area Main comprises a first thin film transistor T1, a first liquid capacitor Old and a first storage capacitor Cst1; the sub area Sub comprises a second thin film transistor T2, a second liquid capacitor Clc2 and a second storage capacitor Cst2. In main area Main, a gate of the first thin film transistor T1 is electrically coupled to the scan line Gn, and a source is electrically coupled to the first data signal line Data1; after the first liquid crystal capacitor Old and the first storage capacitor Cst1 are coupled in parallel, one end is electrically coupled to a drain of the first thin film transistor T1 and the other end is electrically coupled to a constant voltage; in sub area Sub, a gate of the second thin film transistor T2 is electrically coupled to the scan line Gn, and a source is electrically coupled to the second data signal line Data2; after the second liquid crystal capacitor Clc2 and the second storage capacitor Cst2 are coupled in parallel, one end is electrically coupled to a drain of the second thin film transistor T2 and the other end is electrically coupled to a constant voltage. As shown in FIG. 1, FIG. 2, the traditional pixel circuit design can achieve the multi domain display and improves the color shift. However, such design requires to double the amount of the data signal lines, and the amount of the Chip on Films (COF) is also required to be doubled, too. The panel cost will increase.